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Layer shifting or something else?  

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Sunny
(@sunny-4)
New Member
Layer shifting or something else?

Hi,

I've got a MK3 and had some issues with layer shifting in the past. I adjusted the belt tension and tightened the grub screws on the y-axis, that solved the problem.

Now it seems that I have minimal layer shifting or some weird kind of warping, as the first layers were affected but the rest was as it should be. Still, this happens only in the y-axis. Any ideas what this is and how to solve this problem?

Using slicer and PLA as material, that part was printed as a draft. So I guess nozzle speed could also be an issue?

Thanks for any help!

 

Best Answer by --:

Could be the structure of the part.  Is that shift at a layer that is starting to have solid infill for the top layer of something?  First layers of solid infill can curl and catch the nozzle.

Also, improper tightening of the gear set screws is common.  But can also be belt being too tight, bearings not properly lubricated, etc.  Run in normal mode and check for crash detections. If you see any crashes, you need to address whatever is causing the axis to stick.

Flat First: Drive gears must be tightened flat-first.

1)   Start with both set screws fully loosened so the pulley is free to spin on the motor shaft.

2)   Align one set screw dead center with the flat on the motor shaft, slowly tighten the screw until it fully contacts the flat surface.

3)   Torque the flat set screw to spec.

4)   Now tighten the jam set screw, and torque it to spec.

Once tightened, never touch the flat set screw unless the jam screw is first fully loosened.

Why Flat First? Set screws have flat ends. If you tighten the jam screw first the set screw on the shaft flat doesn't fully contact the shaft, only one small edge of the screw surface is biting. Reversing torques can easily shift the shaft to a position the flat screw no longer contacts the shaft. This lets the jam screw wriggle loose. And after a while, vibration loosens the screws until the gear is free to rotate.

Postato : 17/06/2019 5:45 am
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 --
(@)
Illustrious Member
RE: Layer shifting or something else?

Could be the structure of the part.  Is that shift at a layer that is starting to have solid infill for the top layer of something?  First layers of solid infill can curl and catch the nozzle.

Also, improper tightening of the gear set screws is common.  But can also be belt being too tight, bearings not properly lubricated, etc.  Run in normal mode and check for crash detections. If you see any crashes, you need to address whatever is causing the axis to stick.

Flat First: Drive gears must be tightened flat-first.

1)   Start with both set screws fully loosened so the pulley is free to spin on the motor shaft.

2)   Align one set screw dead center with the flat on the motor shaft, slowly tighten the screw until it fully contacts the flat surface.

3)   Torque the flat set screw to spec.

4)   Now tighten the jam set screw, and torque it to spec.

Once tightened, never touch the flat set screw unless the jam screw is first fully loosened.

Why Flat First? Set screws have flat ends. If you tighten the jam screw first the set screw on the shaft flat doesn't fully contact the shaft, only one small edge of the screw surface is biting. Reversing torques can easily shift the shaft to a position the flat screw no longer contacts the shaft. This lets the jam screw wriggle loose. And after a while, vibration loosens the screws until the gear is free to rotate.

Postato : 17/06/2019 5:51 am
Sunny
(@sunny-4)
New Member
Topic starter answered:
RE: Layer shifting or something else?

Thanks for the reply.

Indeed it seems to mark where there are solid layers and infill height. When it stops, it only prints outer walls with no further change to the infill itself.

I'll need to check that on another print.

Postato : 17/06/2019 6:01 am
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